package com.hmdp.utils;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.hmdp.entity.Shop;
import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

import java.time.LocalDateTime;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;

import static com.hmdp.utils.RedisConstants.*;

@Component
@Slf4j
public class CacheClient {

    private final StringRedisTemplate stringRedisTemplate;

    public CacheClient(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    public  void set(String key, Object value, Long time ,  TimeUnit unit) {
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(value), time , unit);
    }

    public  void setWithLogicalExpire(String key, Object value, Long time ,  TimeUnit unit) {

        // 设置逻辑过期
        RedisData redisData = new RedisData();
        redisData.setData(value);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(unit.toSeconds(time)));
        // 写入redis
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(redisData));
    }

    public <R ,ID> R queryWithPassThrough(String keyPrefix , ID id , Class<R> type , Function<ID,R> dbFactory , Long time , TimeUnit unit) {
        String key = keyPrefix + id;
        //从redis中查询商铺缓存
        String Json = stringRedisTemplate.opsForValue().get(key);
        //判断是否存在
        if(StrUtil.isNotBlank(Json))
        {
            //存在，直接返回
            return JSONUtil.toBean(Json, type);
        }
        //不存在，判断是否为空
        if(Json != null)
        {
            //返回错误信息
            return null ;
        }
        //不存在，根据id查询数据库
        R r = dbFactory.apply(id);
        //不存在，返回错误
        if(r == null){
            //将空值写入redis
            stringRedisTemplate.opsForValue().set(key, "",CACHE_NULL_TTL, TimeUnit.MINUTES);
            //返回错误信息
            return null;
        }
        //存在，写入redis
        this.set(key, r, time , unit);
        //返回业务
        return r;
    }

}
